The library
Calculator library
Every calculator shows its full worked solution. Search by name, symbol, or keyword, or filter by category.
68 calculators
Circuit Analysis & Fundamentals
Ohm's Law Calculator & Power Wheel
Solve for voltage, current, resistance, or power from any two known values.
Power Systems Fundamentals
Three-Phase Power Calculator
Solve for real, reactive, and apparent power and power factor from any two known values.
Power Systems Fundamentals
Per-Unit Conversion Calculator
Convert impedance between per-unit bases, or between ohms and per-unit.
Power Systems Fundamentals
Symmetrical Fault Current Calculator
Three-phase bolted fault current at a transformer secondary, from source and transformer impedance.
Power Systems Fundamentals
Voltage Drop Calculator
Percent voltage drop and receiving-end voltage for a feeder or branch circuit.
Power Systems Fundamentals
Power Factor Correction Capacitor Sizing
Required capacitor kVAR and per-phase capacitance to raise power factor to a target value.
Machines & Drives
Induction Motor Equivalent Circuit Solver
Stator current, torque, efficiency, and power factor from R1, X1, R2', X2', Xm at a given slip.
Machines & Drives
Induction Motor Performance from Nameplate
Estimate full-load current, torque, and slip from HP/kW, voltage, poles, efficiency, and power factor.
Machines & Drives
Induction Motor Torque-Speed Curve Generator
Full torque-speed curve from equivalent-circuit parameters, marking starting, breakdown, and rated torque.
Machines & Drives
Motor Starting Current & Voltage Dip Estimator
Locked-rotor starting current and the resulting bus voltage dip for a direct-on-line start.
Machines & Drives
V/Hz Drive Operating Point Calculator
Synchronous speed, commanded voltage, and approximate torque capability for a V/Hz-controlled drive.
Transformers
Transformer Sizing & Full-Load Current Calculator
Primary and secondary full-load current from transformer kVA rating, plus the nearest standard size.
Transformers
Transformer Impedance & Short-Circuit Current Calculator
Symmetrical, peak, and RMS asymmetrical secondary fault current from transformer %Z and X/R ratio.
Cables & Protection
Cable Ampacity & Sizing Assistant
Suggested conductor size from load current, ambient temperature, and raceway grouping derating.
Cables & Protection
Conduit Fill Calculator
Minimum EMT trade size for a given conductor size and count, at the applicable NEC fill percentage.
Cables & Protection
Overcurrent Protection Coordination Checker
Time-current coordination check between two inverse-time overcurrent devices at a specified fault current.
Circuit Analysis & Fundamentals
Resistor Series/Parallel Network Calculator
Equivalent resistance for up to six resistors in series or in parallel.
Circuit Analysis & Fundamentals
Voltage Divider Calculator
Output voltage of a two-resistor divider from the input and both resistors — or solve for the resistor that gives a target output. Shows the divider schematic and loading caveat.
Circuit Analysis & Fundamentals
Current Divider Calculator
Branch currents when a total current splits between two parallel resistors — with the inverse-ratio rule, the shared node voltage, and a labeled schematic.
Circuit Analysis & Fundamentals
Series/Parallel Capacitance & Inductance Calculator
Equivalent capacitance or inductance for series or parallel combinations — with the inverse-vs-resistor rules made explicit so you never mix them up.
Circuit Analysis & Fundamentals
RC / RL Time Constant Calculator
Time constant τ of an RC or RL circuit, the fraction charged/discharged at any time t, and the time to reach a target percentage — with a live charge/discharge curve.
Circuit Analysis & Fundamentals
RLC Resonance Calculator
Resonant frequency, quality factor Q, bandwidth, and damping for a series or parallel RLC circuit — with the resonance curve and half-power points drawn.
Circuit Analysis & Fundamentals
Capacitor & Inductor Energy Calculator
Energy stored in a capacitor (½CV²) or an inductor (½LI²), plus the stored charge or flux linkage — with the quadratic energy curve drawn.
Circuit Analysis & Fundamentals
AC Impedance & Phasor Calculator
Complex impedance of a series or parallel R-L-C combination at a chosen frequency — magnitude, phase, and both rectangular and polar forms, with the impedance-vs-frequency curve.
Circuit Analysis & Fundamentals
Thévenin / Norton Equivalent Calculator
Thévenin voltage and resistance, and the Norton current, for the classic source-behind-R1-with-R2-across-the-terminals network — plus load power and the maximum-power-transfer point.
Circuit Analysis & Fundamentals
Delta–Wye (Δ–Y) Conversion Calculator
Convert a three-resistor network between delta (Δ) and wye (Y / star) form in either direction, with both schematics drawn and the transformation steps shown.
Circuit Analysis & Fundamentals
Wheatstone Bridge Calculator
Balance condition and unknown resistance, or the bridge output (galvanometer) voltage of an unbalanced bridge — with the bridge schematic and the Vg-vs-Rx curve.
Electronics & General Electrical
RC/RL/RLC Time Constant & Resonance Calculator
Time constant for RC/RL circuits, or resonant frequency, Q, and bandwidth for series/parallel RLC.
Electronics & General Electrical
Three-Phase Rectifier Output Calculator
Average DC output voltage and ripple frequency for a 6-pulse three-phase bridge rectifier.
Electronics & General Electrical
Battery Energy Storage Sizing Calculator
Required nameplate battery capacity and C-rate from load power, backup duration, DoD, and efficiency.
Communication Systems
Decibel & dBm Converter
Convert between linear ratios, dB, dBm, and watts, or cascade stage gains and losses to a running power level.
Communication Systems
Free-Space Path Loss (Friis) Calculator
Free-space path loss from frequency and distance, and received power from transmit power, antenna gains, and losses.
Communication Systems
Link Budget Calculator
Received power and link margin from transmit power, antenna gains, feed losses, path loss, and receiver sensitivity.
Communication Systems
Thermal Noise & Noise Figure Calculator
kTB thermal noise power, noise power spectral density, noise temperature from noise figure, and the receiver noise floor.
Communication Systems
Shannon Channel Capacity Calculator
Shannon–Hartley capacity C = B·log₂(1+SNR) — solve for capacity, required SNR, or required bandwidth.
Communication Systems
BER vs Eb/N0 Calculator (AWGN)
Theoretical bit error rate for BPSK, QPSK, and coherent BFSK over an AWGN channel, with the waterfall curve.
Communication Systems
SNR / Eb/N0 / Es/N0 Converter
Convert between SNR, Eb/N0, and Es/N0 given bits per symbol, symbol rate, and bandwidth — the classic source of dB bookkeeping errors.
Communication Systems
AM Modulation Calculator
Modulation index, sideband power, total power, and transmission efficiency for standard full-carrier AM.
Communication Systems
FM Parameters & Carson Bandwidth Calculator
FM modulation index and Carson's rule bandwidth from peak frequency deviation and modulating frequency.
Communication Systems
RC/RL First-Order Filter Calculator
Cutoff frequency, magnitude, and phase of first-order RC and RL low-pass and high-pass filters, with the Bode plot.
Communication Systems
Second-Order (RLC) Filter Calculator
Resonant frequency, Q, bandwidth, and damping for second-order low-pass, high-pass, and band-pass responses, with the Bode plot.
Control Systems
Transfer Function Analyzer
Enter H(s) as polynomial coefficients and get poles, zeros, gain, characteristic equation, system order and type, and a stability verdict — with the pole-zero map and a live step-response preview.
Control Systems
Pole-Zero Analyzer & s-Plane Plot
Poles and zeros on the s-plane with left/right-half-plane classification, the stability verdict, and ζ / ωn of the dominant pole pair.
Control Systems
Step / Impulse / Ramp Response
Simulate the step, impulse, or ramp response of H(s) and read the performance metrics — rise time, peak time, overshoot, settling time — with markers on the curve.
Control Systems
Bode Plot Generator
Magnitude (dB) and unwrapped phase of H(jω) on a log-frequency axis, with gain and phase crossovers located and both stability margins annotated.
Control Systems
Nyquist Plot & Stability Criterion
The L(jω) locus in the complex plane with the −1 point marked, plus the exact Nyquist accounting: open-loop RHP poles P, closed-loop RHP poles Z, and the implied encirclement count N.
Control Systems
Second-Order System Calculator
Sweep ζ and ωn with live sliders and watch the poles move and the step response reshape — with every time- and frequency-domain characteristic computed in closed form.
Control Systems
Stability & Margins Checker
Close the unity-feedback loop around L(s) and check it two independent ways: the Routh–Hurwitz table on the characteristic polynomial, and the gain/phase margins with their crossover frequencies.
Control Systems
PID Controller Analyzer
Tune Kp, Ki, Kd live against your plant: closed-loop step response with metrics, control effort, closed-loop poles, and open-loop margins — all recomputing as you drag.
Control Systems
Ziegler–Nichols PID Tuning
Both classic Ziegler–Nichols methods: closed-loop ultimate gain (Ku, Pu) and open-loop reaction curve (FOPDT), with the tuned gains in both controller forms and a response preview.
Control Systems
Cohen–Coon PID Tuning
Cohen–Coon open-loop tuning from an FOPDT fit (K, T, L) — designed for dead-time-dominant processes — with gains in both forms and a closed-loop preview.
Control Systems
IMC / Lambda PID Tuning
Internal-Model-Control tuning from an FOPDT fit: you choose the closed-loop time constant λ, and the speed-versus-robustness trade-off becomes an explicit engineering decision.
Control Systems
P vs PI vs PID Comparison
One plant, one gain set, three controller structures side by side: what integral action buys (and costs), what derivative action repairs — one chart, one metrics table.
Control Systems
PID Performance Calculator
The complete closed-loop performance report for a tuned PID loop — rise/peak/settling time, overshoot, steady-state error, bandwidth, and margins — exact from the model, or from the second-order approximation, with the validity of that approximation checked.
Signals & Systems
Convolution Calculator
Convolve two discrete sequences, y[n] = Σ x[k]·h[n−k], with the full flip-and-slide breakdown for the selected output sample and stem plots of both inputs and the result.
Signals & Systems
DFT / FFT Spectrum Analyzer
Compute the single-sided amplitude and phase spectrum of a sampled signal (generated from a waveform or entered directly) on a correct hertz axis, with the DFT normalization stated.
Signals & Systems
Fourier Series Calculator
Harmonic coefficients of the standard periodic waveforms with a live N-harmonic partial-sum reconstruction against the ideal — the Gibbs overshoot visible as you add terms.
Signals & Systems
Sampling & Aliasing Calculator
From a signal frequency and a sample rate: the Nyquist rate, whether the tone is aliased, and the exact folded (apparent) frequency the samples appear to contain.
Signals & Systems
Signal Metrics Calculator
RMS, mean, average power, energy, peak, peak-to-peak, and crest factor of a signal — generated from a standard waveform or entered as samples.
Signals & Systems
Frequency Response of an LTI System
Analyze a GIVEN continuous-time LTI system H(s): its magnitude (dB) and phase response H(jω) on a log-frequency axis, evaluated exactly, with the value at any chosen frequency.
Signals & Systems
Step / Impulse Response of an LTI System
Simulate the step or impulse response of a GIVEN continuous-time LTI system H(s), with the standard time-domain metrics (overshoot, rise, peak, settling) for the step.
Digital Logic Design
Karnaugh Map Solver (2–5 Variables)
Click cells or enter minterms and watch the K-map group itself: exact Quine–McCluskey minimization drawn as highlighted groups, with the minimal SOP and POS and a proof of equivalence.
Digital Logic Design
Truth Table Generator
Type a Boolean expression (or a minterm list) and get the complete truth table, the canonical Σm and ΠM forms, and an instant read on tautologies and contradictions.
Digital Logic Design
Boolean Expression Simplifier
Enter any Boolean expression and get the exact minimal SOP and POS — prime implicants, essential implicants, cover selection, and a row-by-row proof that nothing changed but the cost.
Digital Logic Design
SOP ↔ POS Converter
One function, both shapes: canonical and minimal sum-of-products and product-of-sums, with the Σm/ΠM complement relationship made explicit on the truth table.
Digital Logic Design
Logic Gate Evaluator
Every standard gate — AND, OR, NOT, NAND, NOR, XOR, XNOR — with its distinctive-shape symbol, live input toggling, full truth table, and what each gate is actually for.
Digital Logic Design
Number System Converter
Binary, decimal, hex, octal — plus BCD, Gray code, ASCII, and two's-complement encoding/decoding — with the repeated-division and positional-expansion steps written out.
Digital Logic Design
Flip-Flop Characteristic & Excitation Tables
SR, JK, D, and T flip-flops as tables: the characteristic table (what Q⁺ will be) and the excitation table (what inputs force a wanted transition), with a live next-state evaluation.